Jemma Lilley Wanted To Kill Someone Before She Was 26

Teenager Aaron Pajich was murdered by Jemma Lilley because it was her "life's ambition".

Jemma Lilley (left) and Trudi Lenon are accused of killing Aaron Pajich and burying his body.

Teenager Aaron Pajich was murdered by Jemma Lilley because it was her "life's ambition" to kill someone by the time she was aged 25, a WA Supreme Court jury was told.

WA Police

State prosecutor James McTaggart delivered his closing address at the start of the fifth week of the trial of Lilley, 26, and her housemate Trudi Lennon, 43, who are accused of murdering 18-year-old Mr Pajich, who has been described as autistic but "high functioning".

"At the time of the murder she was a person obsessed with violence and all kinds of unquestionably cruel manifestations of torture and was writing about it," he said.